Sql: Include interface for prepared statements.

Signed-off-by: Laurent Aimar <fenrir@videolan.org>

include/vlc_sql.h

@@ -39,11 +39,38 @@ extern "C" {
  * General structure: SQL object.
  *****************************************************************************/
 
+/**
+ * Return values for the function @see sql_Run()
+ */
+#define VLC_SQL_ROW 1
+#define VLC_SQL_DONE 2
+
 typedef struct sql_t sql_t;
 typedef struct sql_sys_t sql_sys_t;
+typedef struct sql_stmt_t sql_stmt_t;
 
 typedef int ( *sql_query_callback_t ) ( void*, int, char**, char** );
 
+typedef enum {
+    SQL_NULL,
+    SQL_INT,
+    SQL_DOUBLE,
+    SQL_TEXT,
+    SQL_BLOB
+} sql_type_e;
+
+typedef struct
+{
+    int length;
+    union
+    {
+        int i;
+        double dbl;
+        char* psz;
+        void* ptr;
+    } value;
+} sql_value_t;
+
 struct sql_t
 {
     VLC_COMMON_MEMBERS
@@ -60,6 +87,7 @@ struct sql_t
     /** Internal data */
     sql_sys_t *p_sys;
 
+    /** All the functions are implemented as threadsafe functions */
     /** Perform a query with a row-by-row callback function */
     int (*pf_query_callback) ( sql_t *, const char *, sql_query_callback_t, void * );
 
@@ -79,12 +107,36 @@ struct sql_t
     int (*pf_begin) ( sql_t* );
 
     /** Commit transaction */
-    void (*pf_commit) ( sql_t* );
+    int (*pf_commit) ( sql_t* );
 
     /** Rollback transaction */
-    void (*pf_rollback) ( sql_t* );
-};
+    int (*pf_rollback) ( sql_t* );
 
+    /** Create a statement object */
+    sql_stmt_t* (*pf_prepare) ( sql_t* p_sql, const char* p_fmt,
+                                int i_length );
+
+    /** Bind parameters to a statement */
+    int (*pf_bind) ( sql_t* p_sql, sql_stmt_t* p_stmt, int i_pos,
+                    unsigned int type, const sql_value_t* p_value );
+
+    /** Run the prepared statement */
+    int (*pf_run) ( sql_t* p_sql, sql_stmt_t* p_stmt );
+
+    /** Reset the prepared statement */
+    int (*pf_reset) ( sql_t* p_sql, sql_stmt_t* p_stmt );
+
+    /** Destroy the statement object */
+    int (*pf_finalize) ( sql_t* p_sql, sql_stmt_t* p_stmt );
+
+    /** Get the datatype for a specified column */
+    int (*pf_gettype) ( sql_t* p_sql, sql_stmt_t* p_stmt, int i_col,
+                        int* type );
+
+    /** Get the data from a specified column */
+    int (*pf_getcolumn) ( sql_t* p_sql, sql_stmt_t* p_stmt, int i_col,
+                          int type, sql_value_t *p_res );
+};
 
 /*****************************************************************************
  * SQL Function headers
@@ -125,7 +177,8 @@ VLC_EXPORT( void, sql_Destroy, ( vlc_object_t *obj ) );
  *             4th is the columns names (array of strings).
  * @param p_opaque Any pointer to an object you may need in the callback.
  * @return VLC_SUCCESS or VLC_EGENERIC.
- * @note The query will not necessarily be processed in a separate thread!
+ * @note The query will not necessarily be processed in a separate thread, but
+ * it is threadsafe
  **/
 static inline int sql_QueryCallback( sql_t *p_sql, const char *psz_query,
                                      sql_query_callback_t pf_callback,
@@ -151,6 +204,7 @@ static inline int sql_QueryCallback( sql_t *p_sql, const char *psz_query,
  * *pi_rows will be the number of result rows, so that the number of text rows
  * in ppsz_result will be (*pi_rows + 1) (because of row 0).
  * To get result[row,col] use (*pppsz_result)[ (row+1) * (*pi_cols) + col ].
+ * This function is threadsafe
  **/
 static inline int sql_Query( sql_t *p_sql, const char *psz_query,
                              char ***pppsz_result, int *pi_rows, int *pi_cols )
@@ -164,6 +218,7 @@ static inline int sql_Query( sql_t *p_sql, const char *psz_query,
  * @param pppsz_tables Pointer to an array of strings. Dynamically allocated.
  * Similar to pppsz_result of sql_Query but with only one row.
  * @return Number of tables or <0 in case of error.
+ * @note This function is threadsafe
  **/
 static inline int sql_GetTables( sql_t *p_sql, char ***pppsz_tables )
 {
@@ -175,6 +230,7 @@ static inline int sql_GetTables( sql_t *p_sql, char ***pppsz_tables )
  * @param p_sql This SQL object.
  * @param ppsz_result The result of sql_Query or sql_GetTables. See above.
  * @return Nothing.
+ * @note This function is threadsafe
  **/
 static inline void sql_Free( sql_t *p_sql, char **ppsz_result )
 {
@@ -215,6 +271,7 @@ static inline char* sql_VPrintf( sql_t *p_sql, const char *psz_fmt,
  * @brief Begin a SQL transaction
  * @param p_sql The SQL object
  * @return VLC error code or success
+ * @note This function is threadsafe
  **/
 static inline int sql_BeginTransaction( sql_t *p_sql )
 {
@@ -225,20 +282,279 @@ static inline int sql_BeginTransaction( sql_t *p_sql )
  * @brief Commit a SQL transaction
  * @param p_sql The SQL object
  * @return VLC error code or success
+ * @note This function is threadsafe
  **/
-static inline void sql_CommitTransaction( sql_t *p_sql )
+static inline int sql_CommitTransaction( sql_t *p_sql )
 {
-    p_sql->pf_commit( p_sql );
+    return p_sql->pf_commit( p_sql );
 }
 
 /**
  * @brief Rollback a SQL transaction
  * @param p_sql The SQL object
  * @return VLC error code or success
+ * @note This function is threadsafe
  **/
-static inline void sql_RollbackTransaction( sql_t *p_sql )
+static inline int sql_RollbackTransaction( sql_t *p_sql )
+{
+    return p_sql->pf_rollback( p_sql );
+}
+
+/**
+ * @brief Prepare an sql statement
+ * @param p_sql The SQL object
+ * @param p_fmt SQL query string
+ * @param i_length length of the string. If negative, length will be
+ * considered upto the first \0 character equivalent to strlen(p_fmt).
+ * Otherwise the first i_length bytes will be used
+ * @return a sql_stmt_t pointer or NULL on failure
+ */
+static inline sql_stmt_t* sql_Prepare( sql_t* p_sql, const char* p_fmt,
+        int i_length )
+{
+    return p_sql->pf_prepare( p_sql, p_fmt, i_length );
+}
+
+/**
+ * @brief Bind arguments to a sql_stmt_t object
+ * @param p_sql The SQL object
+ * @param p_stmt Statement Object
+ * @param type Data type of the value
+ * @param p_value Value to be bound
+ * @param i_pos Position at which the parameter should be bound
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_BindGeneric( sql_t* p_sql, sql_stmt_t* p_stmt,
+        int i_pos, int type, const sql_value_t* p_value )
+{
+    return p_sql->pf_bind( p_sql, p_stmt, i_pos, type, p_value );
+}
+
+/**
+ * @brief Bind a NULL value to a position
+ * @param p_sql The SQL object
+ * @param p_stmt Statement Object
+ * @param i_pos Position at which the parameter should be bound
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_BindNull( sql_t *p_sql, sql_stmt_t* p_stmt, int i_pos )
+{
+    int i_ret = sql_BindGeneric( p_sql, p_stmt, i_pos, SQL_NULL, NULL );
+    return i_ret;
+}
+
+/**
+ * @brief Bind an integer to the statement object at some position
+ * @param p_sql The SQL object
+ * @param p_stmt Statement Object
+ * @param i_pos Position at which the parameter should be bound
+ * @param i_int Value to be bound
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_BindInteger( sql_t *p_sql, sql_stmt_t* p_stmt,
+                                   int i_pos, int i_int )
+{
+    sql_value_t value;
+    value.length = 0;
+    value.value.i = i_int;
+    int i_ret = sql_BindGeneric( p_sql, p_stmt, i_pos, SQL_INT, &value );
+    return i_ret;
+}
+
+/**
+ * @brief Bind a double to the statement object at some position
+ * @param p_sql The SQL object
+ * @param p_stmt Statement Object
+ * @param i_pos Position at which the parameter should be bound
+ * @param d_dbl Value to be bound
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_BindDouble( sql_t *p_sql, sql_stmt_t* p_stmt,
+                                  int i_pos, double d_dbl )
+{
+    sql_value_t value;
+    value.length = 0;
+    value.value.dbl = d_dbl;
+    int i_ret = sql_BindGeneric( p_sql, p_stmt, i_pos, SQL_INT, &value );
+    return i_ret;
+}
+
+/**
+ * @brief Bind Text to the statement
+ * @param p_sql The SQL object
+ * @param p_stmt Statement Object
+ * @param i_pos Position at which the parameter should be bound
+ * @param p_fmt Value to be bound
+ * @param i_length Length of text. If -ve text upto the first null char
+ * will be selected.
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_BindText( sql_t *p_sql, sql_stmt_t* p_stmt, int i_pos,
+                                   char* p_fmt, int i_length )
+{
+    sql_value_t value;
+    value.length = i_length;
+    value.value.psz = p_fmt;
+    int i_ret = sql_BindGeneric( p_sql, p_stmt, i_pos, SQL_TEXT, &value );
+    return i_ret;
+}
+
+/**
+ * @brief Bind a binary object to the statement
+ * @param p_sql The SQL object
+ * @param p_stmt Statement Object
+ * @param i_pos Position at which the parameter should be bound
+ * @param p_ptr Value to be bound
+ * @param i_length Size of the blob to read
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_BindBlob( sql_t *p_sql, sql_stmt_t* p_stmt, int i_pos,
+                                   void* p_ptr, int i_length )
+{
+    sql_value_t value;
+    value.length = i_length;
+    value.value.ptr = p_ptr;
+    int i_ret = sql_BindGeneric( p_sql, p_stmt, i_pos, SQL_INT, &value );
+    return i_ret;
+}
+
+/**
+ * @brief Run the SQL statement. If the statement fetches data, then only
+ * one row of the data is fetched at a time. Run this function again to
+ * fetch the next row.
+ * @param p_sql The SQL object
+ * @param p_stmt The statement
+ * @return VLC_SQL_DONE if done fetching all rows or there are no rows to fetch
+ * VLC_SQL_ROW if a row was fetched for this statement.
+ * VLC_EGENERIC if this function failed
+ */
+static inline int sql_Run( sql_t* p_sql, sql_stmt_t* p_stmt )
+{
+    return p_sql->pf_run( p_sql, p_stmt );
+}
+
+/**
+ * @brief Reset the SQL statement. Resetting the statement will unbind all
+ * the values that were bound on this statement
+ * @param p_sql The SQL object
+ * @param p_stmt The sql statement object
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_Reset( sql_t* p_sql, sql_stmt_t* p_stmt )
+{
+    return p_sql->pf_reset( p_sql, p_stmt );
+}
+
+/**
+ * @brief Destroy the sql statement object. This will free memory.
+ * @param p_sql The SQL object
+ * @param p_stmt The statement object
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_Finalize( sql_t* p_sql, sql_stmt_t* p_stmt )
+{
+    return p_sql->pf_finalize( p_sql, p_stmt );
+}
+
+/**
+ * @brief Get the datatype of the result of the column
+ * @param p_sql The SQL object
+ * @param p_stmt The sql statement object
+ * @param i_col The column
+ * @param type pointer to datatype of the given column
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_GetColumnType( sql_t* p_sql, sql_stmt_t* p_stmt,
+        int i_col, int* type )
+{
+    return p_sql->pf_gettype( p_sql, p_stmt, i_col, type );
+}
+
+/**
+ * @brief Get the column data
+ * @param p_sql The SQL object
+ * @param p_stmt The statement object
+ * @param i_col The column number
+ * @param type Datatype of result
+ * @param p_res The structure which contains the value of the result
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_GetColumn( sql_t* p_sql, sql_stmt_t* p_stmt,
+        int i_col, int type, sql_value_t *p_res )
+{
+    return p_sql->pf_getcolumn( p_sql, p_stmt, i_col, type, p_res );
+}
+
+/**
+ * @brief Get an integer from the results of a statement
+ * @param p_sql The SQL object
+ * @param p_stmt The statement object
+ * @param i_col The column number
+ * @param i_res Pointer of the location for result to be stored
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_GetColumnInteger( sql_t* p_sql, sql_stmt_t* p_stmt,
+        int i_col, int* pi_res )
+{
+    sql_value_t tmp;
+    int i_ret = p_sql->pf_getcolumn( p_sql, p_stmt, i_col, SQL_INT, &tmp );
+    if( i_ret == VLC_SUCCESS )
+        *pi_res = tmp.value.i;
+    return i_ret;
+}
+
+/**
+ * @brief Get a double from the results of a statement
+ * @param p_sql The SQL object
+ * @param p_stmt The statement object
+ * @param i_col The column number
+ * @param d_res Pointer of the location for result to be stored
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_GetColumnDouble( sql_t* p_sql, sql_stmt_t* p_stmt,
+        int i_col, double* pd_res )
+{
+    sql_value_t tmp;
+    int i_ret = p_sql->pf_getcolumn( p_sql, p_stmt, i_col, SQL_DOUBLE, &tmp );
+    if( i_ret == VLC_SUCCESS )
+        *pd_res = tmp.value.dbl;
+    return i_ret;
+}
+
+/**
+ * @brief Get some text from the results of a statement
+ * @param p_sql The SQL object
+ * @param p_stmt The statement object
+ * @param i_col The column number
+ * @param pp_res Pointer of the location for result to be stored
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_GetColumnText( sql_t* p_sql, sql_stmt_t* p_stmt,
+        int i_col, char** pp_res )
+{
+    sql_value_t tmp;
+    int i_ret = p_sql->pf_getcolumn( p_sql, p_stmt, i_col, SQL_TEXT, &tmp );
+    if( i_ret == VLC_SUCCESS )
+        *pp_res = tmp.value.psz;
+    return i_ret;
+}
+
+/**
+ * @brief Get a blob from the results of a statement
+ * @param p_sql The SQL object
+ * @param p_stmt The statement object
+ * @param i_col The column number
+ * @param pp_res Pointer of the location for result to be stored
+ * @return VLC_SUCCESS or VLC_EGENERIC
+ */
+static inline int sql_GetColumnBlob( sql_t* p_sql, sql_stmt_t* p_stmt,
+        int i_col, void** pp_res )
 {
-    p_sql->pf_rollback( p_sql );
+    sql_value_t tmp;
+    int i_ret = p_sql->pf_getcolumn( p_sql, p_stmt, i_col, SQL_BLOB, &tmp );
+    if( i_ret == VLC_SUCCESS )
+        *pp_res = tmp.value.ptr;
+    return i_ret;
 }
 
 # ifdef __cplusplus